/****************************************************************************
**
** Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies).
** All rights reserved.
** Contact: Nokia Corporation (qt-info@nokia.com)
**
** This file is part of the Qt Components project.
**
** $QT_BEGIN_LICENSE:BSD$
** You may use this file under the terms of the BSD license as follows:
**
** "Redistribution and use in source and binary forms, with or without
** modification, are permitted provided that the following conditions are
** met:
**   * Redistributions of source code must retain the above copyright
**     notice, this list of conditions and the following disclaimer.
**   * Redistributions in binary form must reproduce the above copyright
**     notice, this list of conditions and the following disclaimer in
**     the documentation and/or other materials provided with the
**     distribution.
**   * Neither the name of Nokia Corporation and its Subsidiary(-ies) nor
**     the names of its contributors may be used to endorse or promote
**     products derived from this software without specific prior written
**     permission.
**
** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
** $QT_END_LICENSE$
**
****************************************************************************/

import QtQuick 1.1

QtObject {
    id: root
    property bool checked: false
    property variant value: null
    property QtObject exclusiveGroup: null
    property bool enabled: false

    onEnabledChanged: {
        if (!enabled) {
            exclusiveGroup = null;
            checked = false;
        }
    }

    function toggle() {
        if (!enabled)
            return;
        if (!exclusiveGroup) {
            checked = !checked;
        } else {
            // In an exclusive group, there is no 'checked = false'. The invariant
            // of the group doesn't allow to "uncheck" the checked item. Note that
            // the group watches for changes in the checked variable of its items.
            checked = true;
        }
    }

    onExclusiveGroupChanged: {
        if (exclusiveGroup) {
            enabled = true;
            // Note that we don't need to remove the previous group,
            // since it is watching the 'exclusiveGroup' property changes
            // in this item and will automatically remove us.
            exclusiveGroup.__add(root);
        }
    }

    Component.onDestruction: {
        // If there's a previous group, it will be watching for
        // this change and will remove this item.
        exclusiveGroup = null;
    }
}
